friden



C. M. F. FRIDEN CALCULATING MACHINE June 19,1928. 1,674,170

Filed June 29, 1925 BY /Mnnnns Patented .lune 19, i923 jaw CARL M. r. naman, or onstaan, catironma.

CALCULATING MACHINE.

Application led Jiune 29, 1925. Serial No. 40,221.

The invention relates to calculating maehines in which the values to be calculated are entered into the machine by the depression of keys. These values are transmitted by the depression of keys, through levers or other mechanism to a value selecting unit. It is essential that the value selecting unit be accurately positioned in its variable settings so that the result produced by the operation of the machine will be correct. Due to the possibility of lost motion between the key and the value selecting unit,

said unit may be improperly positioned by 3 the depression of a'value key. 'lhislost motion may occur due to wear ofcoacting parts or due to slight inaccuracies in the dimensions of the cooperating parts.

An object of the present invention is to provide a structure connecting the key with the value selecting unit; which will cause the depression of. a value key. to set the value selecting unit in correct adjusted position, regardless of slight wear or slight inaccuracies of dimensions of the parts.

Another object ofthe invention is to provide a value selecting unit positioning lever carrying a rack which is resiliently urged into snug mesh with a gear secured to the value selecting unit, so that there is no lost" motion between the rack and the gear, this being the place at which lost motion may otherwise most probably occur.

The invention possesses other advantageous features, some of which with the foregoing will be set forth at length in the following i description where I shall outline in full that form of the inventionvwhich I have selected for illustration in the drawings accompanying and forming part of the present speciication.. In said drawings l have shown one form of device for properly positioning the value selecting units, but it is to be` understood that l do not limit myself to such form, since the invention, as set forth in the claims, may be embodied in other forms.

Referring to said drawings:

Figure 1 is a vertical longitudinal section through tone typel of calculating machine, showing the device of my invent-ion in its environment. l Y

Figure 2 is an elevation on a larger scale of the value selecting unit positioning lever, the heads of the screws being removed to show the construction.

4preferably formed in two yie'ldingly urged apart,

Figure 3 is an end elevation ofthe lever shown in Figure 2, parts thereof being broken away to disclose the construction.

The present invention is particularly applicable to calculating machines of the .type disclosed in my Patent No. 1,524,924 issued February 3, 1925.. A calculating machine of this character comprises a selectingelement 3 which functions during the operation of the machine to cause the counting mechanism 4 to beperated a number of times corresponding to the value represented `by the ad- 'usted position of the value selecting units. This unit -is moved to selected adjusted position byf the 4depression of o ne of a series of numeral keys 2, each key corresponding to a different value, from l to 9, successively. Depression of the numeral key 2 bearing the numeral designation 9 positions the value selecting unit 8`so that operation of the machine causes the counting mechanism to be moved nine steps. rlhe setting movement is transmitted from the value key tothe Value selecting unit by a lever 9, with which the key shanks cooperate and a bell-crank lever 6 carrying on its end a rack 7 which meshes with a gear 8 which is secured to the value value key 2, which may result in the introduction of errors into the calculation. vIn

accordance with my 'invention il have provided means for producing a more positive connection between the lever 6 and the gear 8, so that the value selecting units will always be accurately positioned. In the present instance, this is; accomplished by providing means for maintaining the rack in snug meshing engagement with the gear 8, so that lost motion will not occur at this place.- I

AFor this purpose one arm of the lever 6 is parts which are thu's yieldingly pressing the rack 7 into engagement with the gear 8.

The lever arm 12 of the lever (iis provided with an extension arm 13 which carv ries the rack'7 and resilient means is inter- 4posed between the arms 12 and 13 to urge them apart. The lever arm 12 is provided with two slots 14 and 15 which are prefer ably in falinement and preferably radiallly)r disposed with respect to the rod 16 on whic the'lever 6 is fulcrumed. Seated in the' exoverlying the slots to hold the two lever longerthanthe diameters of the body. portion ofthe screws 17 so ,that the extension farm 13 has a sliding movement with rej fus:

spect to the lever arm 12, in a direction substantiallyradial with respect to the rod 16.

. The two lever arms l12 and 13 are urged apart by a compression spring 21 interposed.

[between anfear. 22 on the extension arm 13 and an ear 23 on the lever 6. This spring holds the rack 7 in snug pressure engagement with the gear l8, so that no 'lost motion occurs between the rack and the gearn Should the teeth of the rack or gear wear due to lon continued use, the spring urges the two arms A12-and 13 further apart, causing the teeth on the rack-to seatsnugly between` the teeth on the gear. Further,

,- -should there be. any slight inaccuracy of di- 30 mension the lever, this inaccuracy is com my hand. l

pensated lfor by arm of the lever.

yI claim:

1.v The combination with a gear, of a lever having an arm, an extension arm slidably connected to said lever arm, a rack on the extension arm meshing with the gear and a y compressed spring intr osed between the lever arm and the extenslon arm to hold the rack in pressure engagement with the ear.

2. The combination with a gear, of a ever having an arm', an4 extension arm slidably connected to said lever arm, a rack on the extension arm meshing with the gear,'an ear on the lever arm, an ear o n the extension arm and a compression spring arranged between lsaid ears to -hold the rack in pressure engagementpwith the. gear. .p

3. The eombinationwith a gear; of an arcuate rack in continuous mesh 'with said gear and adapted to preciselyposition said gear, a lever arm comprising two relatively movable parts, one part bein fulcrumed and the other part earryin vt e rack, and resilient means arranged to old the rack in continuous pressure engagement with the gear.

` In testimony whereof,

Athe yieldingly extensible l1E have hereunto set CARL M. F. .FRIDEN. 

